1. Field of the Invention
The present invention relates to optical communication equipment and, more specifically but not exclusively, to multipath channels for optical subcarrier modulation.
2. Description of the Related Art
This section introduces aspects that may help facilitate a better understanding of the invention(s). Accordingly, the statements of this section are to be read in this light and are not to be understood as admissions about what is in the prior art or what is not in the prior art.
Optical MIMO (multiple in, multiple out) methods are being actively developed to exploit the inherently high transmission capacity of multipath (e.g., multimode and/or multi-core) optical fibers. However, one problem with a multipath optical fiber is that it subjects the optical communication signals that are being transmitted therethrough to stochastic amplitude fading. Due to the amplitude fading, the optical communication channel established over a multipath fiber may have instantiations whose maximum MIMO capacities are lower than the minimum MIMO capacity permitted by the FEC (forward error correction) coding implemented in the system. During such channel instantiations, the transmitted optical signal becomes un-decodable at the receiver, which disadvantageously produces a system outage that may persist for an extended period of time, for example, until the MIMO capacity of the channel recovers to a higher level.